Proppants and Methods of Making the Same

Patent metadata

Field	Value
Publication number	US-2016376199-A1
Application number	US-201414903457-A
Country	US
Kind code	A1
Filing date	Aug 6, 2014
Priority date	Aug 7, 2013
Publication date	Dec 29, 2016
Grant date	—

Abstract

Synthetic ceramic proppants are described. Methods to make these proppants and methods of using these proppants are also described.

First claim

What is claimed is:

1 . A proppant comprising a porous core and a shell surrounding the core, the shell including a transition region and an outer shell surrounding the transition region, wherein an average transition region density is greater than an average outer shell density and the average shell density is greater than an average core density.

2 . The proppant of claim 1 , wherein the average transition region density is at least 5% greater than the average outer shell density, and/or the average transition region density is at least 5% greater than the average core density.

3 . The proppant of claim 1 , wherein the core is substantially hollow.

4 . The proppant of claim 1 , wherein the core, the transition region, the outer shell, or any combination thereof comprises graphene.

5 . A proppant comprising a porous core, a transition region surrounding the core, and an outer shell surrounding the transition region, wherein an average transition region porosity is less than an average outer shell porosity and the average outer shell porosity is less than an average core porosity.

6 . The proppant of claim 5 , wherein a) the average transition region porosity is less than the average outer shell porosity, or b) the average transition region porosity is less compared to the average core porosity, or both a) and b).

7 . The proppant of claim 5 , wherein the core is substantially hollow and the average core porosity is about 100 vol % based on the total volume of the core.

8 .- 20 . (canceled)

21 . A method of making a sintered ceramic proppant comprising:
forming a substantially spherical green body core comprising one or more ceramic particulate materials; forming, at the same time or afterwards, a green body shell around the green body core, wherein the green body shell comprises at least one ceramic particulate material that results in a green core/shell body; sintering the green core/shell body, and, during sintering, diffusing (or otherwise migrating) at least a portion of the green body core into the green body shell to form a sintered ceramic proppant comprising a porous core, a transition region surrounding the core, and an outer shell surrounding the transition region, wherein an average transition region density is greater than an outer average shell density and the average outer shell density is greater than an average core density.

22 . The method of claim 21 , wherein the sintering comprises heating the green/core shell body to at least 500° C.

23 .- 25 . (canceled)

26 . The method of claim 21 , wherein the green body core has a weight ratio of SiO 2 to Al 2 O 3 of 2.3 or higher and a combined weight percentage of Na 2 O and K 2 O of 5.0 or higher based on the total dry weight of the core.

27 . The method of claim 21 , wherein the green body core comprises at least 5.0 wt % of components having a melting point of less than 1200° C. and less than 95 wt % of components having a melting point greater than 1200° C. based on the total dry weight of the core.

28 . The method of claim 21 , wherein the green body core comprises at least 5.0 wt % of components having a melting point of less than 1200° C., less than 7.0% wt % of components having a melting point greater than 1200° C. and less than 1500° C., and less than 88 wt % of components having a melting point greater than 1500° C. based on the total dry weight of the core.

29 . The method of claim 21 , wherein the green body core comprises at least 5.0 wt % of components having a melting point of less than 1200° C., less than 92 wt % of components having a melting point greater than 1200° C. and less than 2100° C., and less than 3.0 wt % of components having a melting point greater than 2100° C. based on the total dry weight of the core.

30 . The method of claim 21 , wherein the green body core comprises one or more fluxing agents and one or more non-fluxing ceramic materials, wherein the melting points of the fluxing agents are less than the melting points than the non-fluxing ceramic materials.

31 . The method of claim 21 , sintered ceramic proppant comprises a substantially hollow core.

32 .- 39 . (canceled)

40 . A proppant comprising a porous core, and a shell surrounding the porous core and comprising a transition region and an outer shell surrounding the transition region, wherein an average transition region density is greater than an average outer shell density, the average outer shell density is greater than an average core density, and the transition region has a glassy phase content of at least 5 vol % based on the total volume of the transition region.

41 . The proppant of claim 40 , wherein the porous core, the transition region, the outer shell, or any combination thereof comprises graphene.

42 .- 85 . (canceled)

86 . A method of forming a conductive ceramic proppant comprising
forming a green body comprising graphene, the green body comprising a core, a shell, or both; heating the green body under controlled heating conditions; and sintering the heated green body at an elevated temperature to form a conductive ceramic proppant.

87 . The method of claim 86 , wherein the conductive ceramic proppant is thermally conductive, electrically conductive, or both.

88 .- 90 . (canceled)

Assignees

• Halliburton Energy Services Inc

Inventors

• Koep Erik
• Khadilkar Chadra
• Fang Christopher Y

Classifications

• C04B2235/422

  Carbon · CPC title

• C04B2235/6028

  Shaping around a core which is removed later · CPC title

• C04B2235/528

  Spheres · CPC title

• C04B35/52 Primary

  based on carbon, e.g. graphite · CPC title

• C09K8/80

  Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open · CPC title